Connectors

ABSTRACT

The connector of the present invention has a housing formed from a polyamide resin composition which comprises 65-85% by weight of a specific polyamide (A), and 5-20% by weight of a graft-modified α-olefin random copolymer and/or graft-modified vinyl aromatic hydrocarbon/conjugated diene copolymer or a hydrogenation product thereof (B), and 0.1-1.0% by weight, based on 100% by weight of the total of the aromatic polyamide (A) and graft-modified copolymer (B), of a polyethylene wax or a metallic salt of an aliphatic carboxylic acid having 26-32 carbon atoms (C), and further, optionally, an antioxidant (D). 
     An object of the present invention is to provide a connector which is free from a decrease in characteristics such as toughness by heating, and, in particular, can be formed with excellent moldability, and is light weight.

FIELD OF THE INVENTION

This invention relates to connectors, in particular those which do notdeteriorate their characteristics, such as toughness, by heating, can beprepared with excellent molding workability, and are especially suitablefor use in automobiles.

TECHNICAL BACKGROUND

As plastic materials for automotive connectors, there have been used,for example aliphatic polyamides (PA 66, PA 6) and polybutyleneterephthalate (PBT).

However, aliphatic polyamides tend to absorb water to decrease modulusof elasticity, so that there have been a problem that when a connectormade of an aliphatic polyamide is used in water or under conditions ofhigh humidity, the connector may loose its firm fitting and even may betaken out. On the other hand, connectors made of PBT are heavy due toits high specific gravity. There is also a problem that heat resistanceof PBT is not always sufficient.

Water absorption characteristics of aliphatic polyamides can be improvedby combining it with an aromatic polyamide (see Japanese PatentApplication No. 2-85,208).

However, such combination of aliphatic and aromatic polyamides may leadto poor moldability. Such poor moldability can be improved by elevatinga molding temperature, but this gives rise to a new problem that where aconnector of a certain shape is to be molded, it may sometimes stick inthe mold.

In order to solve such problem of poor mold release associated with theuse of an aromatic polyamide, an attempt to improve the moldreleasability by the addition of a mold release agent to the aromaticpolyamide has been proposed, for example, in JP-A-3-163,165. The moldrelease agent used therein includes metallic salts of higher fattyacids, for example calcium stearate and derivatives of aliphaticcarboxylic acids such as aliphatic alcohol esters of montanic acid,which can also usable as form release agents for aliphatic polyamides.

It has been found, however, that when a mold release agent, for exampledisclosed in the above-mentioned JP-A, is added to a compositioncomprising an aromatic polyamide, the mold release agent may evolve gasand foam during a molding step to lead deterioration of properties ofconnectors obtained. This is because an aromatic polyamide has a highermelting point than an aliphatic polyamide so that a compositioncomprising an aromatic polyamide must be molded at a temperature higherthan that of a composition comprising an aliphatic polyamide. That is,even if it is intended to prepare connectors from the aromatic polyamidecomposition containing the compound used as the mold release agent foraliphatic polyamide as mentioned above, such compound may decompose atthe molding temperature to foam and cannot effectively function as themold release agent, resulting in poor mold releasing of the connectors.Further, because of such poor moldability, there may be obtainedconnectors which sometimes do not have intendedly improvedcharacteristics such as toughness.

An object of the present invention is to provide lightweight connectorswhich do not deteriorate their characteristics, such as toughness, byheating, and can be prepared with excellent molding workability.

DISCLOSURE OF THE INVENTION

The connector of the present invention has a housing which is formedfrom a polyamide resin composition comprising

(A) 65-90% by weight of an aromatic polyamide having an intrinsicviscosity (η), as measured in a concentrated sulfuric acid at 30° C., of0.5-3.0 dl/g and a melting point of exceeding 300° C.,

said aromatic polyamide (A) being composed of

recurring units comprising 50-100 mol % of terephthalic acid constituentunits, 0-50% by mol of aromatic dicarboxylic acid constituent unitsother than the terephthalic acid units and/or 0-50% by mol of aliphaticdicarboxylic acid constituent units, each of which has 4 to 20 carbonatoms, and

recurring units comprising aliphatic alkylenediamine constituent unitsand/or alicyclic alkylenediamine constituent units; and

(B) 10-35% by weight of a graft-modified α-olefin random copolymerand/or a graft-modified vinyl aromatic hydrocarbon/conjugated dienecopolymer or a hydrogenation product thereof, with the proviso that thesum total of aromatic polyamide (A) and graft-modified copolymer (B) is100% by weight; and

(C) 0.1-1.0% by weight, based on 100% by weight of the sum total ofaromatic polyamide (A) and graft-modified copolymer (B), of at least onecompound selected from the group consisting of polyethylene waxes andmetallic salts of aliphatic carboxylic acids having 26-32 carbon atoms.

The polyamide resin composition according to the invention may furthercontain an antioxidant (D) along with the components (A), (B) and (C),and in this case it is desirable that the antioxidant (D) comprises ahindered phenol antioxidant preferably having a molecular weight of atleast 500 and a sulfur antioxidant preferably having a molecular weightat least 600.

In the aromatic polyamide (A) according to the invention, it ispreferable that the dicarboxylic acid constituent units comprise 50-80%by mol of terephthalic acid constituent units, 0-40% by mol of aromaticdicarboxylic acid component unit other than the terephthalic acid units,and 20-50% by mol of aliphatic dicarboxylic acid constituent units.

The graft-modified α-olefin random copolymer and/or graft-modified vinylaromatic hydrocarbon/conjugated diene copolymer or hydrogenated productthereof (B) is preferably a graft-modified ethylene/propylene copolymer.

The metallic salt of aliphatic carboxylic acid having 26-32 carbon atomsis preferably sodium montanate.

The present invention has been accomplished on the basis of the findingthat by incorporating a specific compound as a mold release agent (C)into a specific aromatic polyamide (A) and a graft-modified elastomericcopolymer (B) , a very good moldability of the composition can beensured.

The connector of the present invention has a housing formed from acomposition comprising an aromatic polyamide, a graft-modifiedelastomeric copolymer and a specific compound acting as a mold releaseagent in specific proportions. That is, the composition used accordingto the invention provides a connector with excellent moldingworkability, and the connector is lightweight due to its low specificgravity and has very high heat resistance.

BRIEF DESCRIPTION OF THE DRAWINGS

FIG. 1 is a perspective view showing an example of housings for aconnector of the present invention;

FIG. 2 is a sectional view showing the housings of FIG. 1 which areconnected to each other; and

FIG. 3 is a schematic view showing the structure of a device used formeasuring a mold release force.

Meanings of reference numbers:

1 . . . Female housing

2 . . . Male housing

3a . . . Terminal inserting chamber

3b . . . Terminal inserting chamber

4 . . . Female terminal

5a . . . Hooking member (lance)

6 . . . Male terminal

11 . . . Sprue runner

12 . . . Molded article (cup-like article)

13 . . . Pushing pin

14 . . . Pressure sensor

15 . . . Mold release force recorder

16 . . . Male mold

17 . . . Female mold

BEST MODE FOR CARRYING OUT THE INVENTION

The connectors of the present invention are illustrated in more detailhereinafter.

The connectors of the present invention are formed from a resincomposition comprising a specific aromatic polyamide (A), a specificgraft-modified elastomeric copolymer (B), and a mold release agent (C),and, optionally, an antioxidant (D), the description of these componentswill follow.

Aromatic Polyamide (A)

The aromatic polyamide (A) is composed of recurring units derived fromspecific dicarboxylic acid constituent units (a), and specific aliphaticdiamine constituent units or alicyclic diamine constituent units (b).

The specific dicarboxylic acid constituent units (a) compriseterephthalic acid constituent units (a-1) as essential constituentunits. The recurring units of the terephthalic acid constituent units(a-1) may be represented by the following formula [I-a]: ##STR1##wherein R¹ is a divalent hydrocarbon group, preferably an alkylene grouphaving 4-18 carbon atoms.

All of the specific dicarboxylic acid constituent units (a) need notnecessarily be composed of the constituent units represented by theabove formula [I-a], and a part of the terephthalic acid constituentunits (a-1) may be replaced by other dicarboxylic acid constituentunits.

Such dicarboxylic acid constituent units other than the terephthalicacid constituent units include aromatic dicarboxylic acid constituentunits (a-2) and aliphatic dicarboxylic acid constituent units (a-3).

Examples of the aromatic dicarboxylic acid constituent units (a-2)include constituent units derived from isophthalic acid, 2-methylterephthalic acid and naphthalene dicarboxylic acid, and isophthalicacid constituent units are especially preferred.

Of the aromatic dicarboxylic acid constituent units (a-2) other thanterephthalic acid, the isophthalic acid constituent units particularlypreferred in the invention may be represented by the following formula[I-b]: ##STR2## wherein R¹ is a divalent hydrocarbon group, preferablyan alkylene group having 4-18 carbon atoms.

The aliphatic dicarboxylic acid constituent units (a-3) are derivedusually from aliphatic dicarboxylic acids having 4-20 carbon atoms,preferably 6-12 carbon atoms in an alkylene group. Examples of thealiphatic dicarboxylic acids used for deriving such aliphaticdicarboxylic acid constituent units (a-3) include succinic acid, adipicacid, azelaic acid and sebacic acid.

Where the polyamide comprises the aliphatic dicarboxylic acidconstituent units, it is particularly preferable that these units arederived from adipic acid and sebacic acid.

The recurring units of the aliphatic dicarboxylic acid constituent units(a-3) constituting the dicarboxylic acid constituent units (a) may berepresented by the following formula [II]: ##STR3## wherein R¹ has thesame meaning as defined above, and n is an integer of usually 2-18,preferably 4-10.

The recurring units constituting the polyamide used in the presentinvention comprise the dicarboxylic acid constituent units (a) and thediamine constituent units (b) as mentioned above.

The diamine constituent units (b) may be derived from aliphatic alkylenediamines and/or alicyclic diamines having 4-18 carbon atoms.

Specific examples of the aliphatic alkylene diamines include1,4-diaminobutane, 1,6-diaminohexane, trimethyl-1,6-diaminohexane,1,7-diaminoheptane, 1,8-diaminooctane, 1,9-diaminononane,1,10-diaminodecane, 1,11-diaminoundecane and 1,12-diaminododecane. Aspecific example of the alicyclic diamines include diaminocyclohexane.

Preferred diamine constituent units used in the present invention arethose derived from straight chain aliphatic alkylene diamines,particularly 1,6-diaminohexane, 1,8-diaminooctane, 1 10-diaminodecane,1,12-diaminododecane and mixtures thereof. Of these constituent units,especially preferred are those derived from 1,6-diaminohexane.

In the aromatic polyamide (A) used in the present invention, the contentof the terephthalic acid constituent units (a-1) is 50-100% by mol,preferably 50-80% by mol, more preferably 50-70% by mol; the content ofthe aromatic dicarboxylic acid constituent units other than terephthalicacid (a-2) is 0-50% by mol, preferably 0-40% by mol, more preferably0-20% by mol; and the content of the aliphatic dicarboxylic acidconstituent units (a-3) is 0-50% by mol, preferably 10-50% by mol, morepreferably 20-50% by mol, particularly 30-50% by mol, with the provisothat the total dicarboxylic acid constituent units is 100% by mol.

The polyamide used according to the present invention may contain smallamounts of constituent units derived from polyvalent carboxylic acidshaving at least tribasicity such as trimellitic acid or pyromelliticacid, in addition to the above-mentioned essential constituent units,i.e. the terephthalic acid constituent units, and optionally theconstituent units derived from aromatic dicarboxylic acids other thanterephthalic acid, representative of which is isophthalic acid, andoptionally the aliphatic dicarboxylic acid constituent units. Suchconstituent units derived from polyvalent carboxylic acid are usuallycontained in the aromatic polyamide (A) in an amount of 0-5% by mol.

The aromatic polyamide (A) may be a mixture comprising an aromaticpolyamide composed mainly of the recurring units of the above formula[I-a] and an aromatic polyamide composed mainly of the recurring unitsof the above formula [I-b]. In this case, the content of the aromaticpolyamide composed mainly of the recurring units of the formula [I-a] isusually not less than 50% by weight, preferably not less than 55% byweight.

The aromatic polyamide (A) used in the present invention has anintrinsic viscosity (η), as measured in a concentrated sulfuric acid at30° C., is usually 0.5-3.0 dl/g, preferably 0.5-2.8 dl/g and especially0.6-2.5 dl/g. The content of amino groups in the aromatic polyamide, asmeasured by neutralization titration in a metacresol solution withp-toluenesulfonic acid, is usually 0.04-0.2 milli equivalent/g,preferably 0.045-0.15 milli equivalent/g and especially 0.5-0.1 milliequivalent/g.

Because of its composition as mentioned above, the aromatic polyamide(A) has a melting point higher than that of an aliphatic polyamideconventionally used hitherto. That is, the aromatic polyamide (A) usedin the invention has a melting point exceeding 300° C. and the aromaticpolyamide (A) having a melting point of preferably 305°-340° C. morepreferably 310°-330° C. exhibits excellent heat resistance. Further, theglass transition temperature of an amorphous portion of the aromaticpolyamide (A) is usually at least 80° C.

Because of its specific structure, the aromatic polyamide according tothe invention exhibits a low water absorption value, whereasconventional aliphatic polyamides have been accompanied by a problem ofhigh water absorption values.

Although the aromatic polyamide as mentioned above has a low value ofwater absorption and favorable heat resistance, it has been found thatthis aromatic polyamide tends to have low toughness as compared withaliphatic polyamides, and this may cause another problem that moldedarticles formed therefrom are insufficient in elongation or brittle.Because a high level of reliability is required in particular forautomotive parts, it is an important subject that a further improvementin toughness of the aromatic polyamide is attained.

Graft-Modified Copolymer (B)

The resin composition from which the connectors of the present inventionare formed contains a graft-modified elastomeric α-olefin randomcopolymer and/or a graft-modified vinyl aromatic hydrocarbon/conjugateddiene copolymer or a hydrogenation product thereof (B).

The graft-modified α-olefin random elastomeric copolymer used in thepresent invention is a graft-modified product of a copolymer in whichtwo types of recurring units derived from different α-olefins arearranged at random.

The graft-modified α-olefin random elastomeric copolymer has a lowcrystallinity or is amorphous, and it is preferable that this copolymeris substantially amorphous. That is, this copolymer has a crystallinity,as measured by X-ray diffractometry, of not more than 10%, preferablynot more than 5%, particularly 0%. Accordingly, many of thegraft-modified α-olefin random elastomeric copolymers do not exhibit anydistinct melting point. Further, because of their low crystallinity, thegraft-modified α-olefin random elastomeric copolymers are soft and havea tensile modulus of usually at least 0.1 kg/cm² and lower than 20000kg/cm², preferably from 1 kg/cm² to 15000 kg/cm².

The graft-modified α-olefin random copolymer has a melt index (asmeasured at 190° C.) of usually 0.1-30 g/10 min, preferably 1.0-20 g/10min, especially 2.0-15 g/10 min, and a value of Mw/Mn, as measured byGPC, of usually not more than 5.5, preferably not more than 4.5,especially not more than 3.5.

Further, this graft-modified α-olefin random elastomeric copolymer has aglass transition temperature (Tg) of usually -150°to +50° C., preferably-80°to -20° C., and an intrinsic viscosity (η), as measured in decalinat 135° C., of usually 0.2-10 dl/g, preferably 1-5 dl/g, and a densityof usually 0.82-0.96 g/cm³, preferably 0.84-0.92 g/cm³.

Specific examples of the graft-modified α-olefin random elastomericcopolymers having the above-mentioned characteristics include agraft-modified ethylene/α-olefin copolymer rubber (i) comprisingethylene as a major monomer and a graft-modified propylene/α-olefincopolymer rubber (ii) comprising propylene as a major monomer.

By way of typical examples of the graft-modified α-olefin randomelastomeric copolymers as mentioned above, the graft-modifiedethylene/α-olefin copolymer rubber (i) and the graft-modifiedpropylene/α-olefin copolymer rubber (ii) are illustrated below in moredetail.

For the graft-modified ethylene/α-olefin copolymer rubber (i), α-olefinshaving usually 3-20 carbon atoms are used. Examples of these α-olefinsinclude propylene, butene-1, pentene-1, hexene-1 ,4-methylpentene-1,octene-1, decene-1 and mixtures thereof. Of those, propylene and/orbutene-1are particularly preferred.

For the graft-modified propylene/α-olefin copolymer rubber (ii),α-olefins having usually 4-20 carbon atoms are used. Examples of theseα-olefins include butene-1, pentene-1, hexene-1 , 4-methylpentene-1,octene-1, decene-1 and mixtures thereof. Of those, butene-1 isparticularly preferred.

In the graft-modified ethylene/α-olefin copolymer rubber (i) asmentioned above, the molar ratio (ethylene/α-olefins of ethylene toα-olefin is generally 10/90 to 99/1, preferably 50/50 to 95/5, though itvaries depending on the types of α-olefins used. When the α-olefin usedis propylene, the molar ratio is preferably 50/50 to 90/10, especially70/30 to 85/15. When the α-olefin used is one having at least 4 carbonatoms, the molar ratio is preferably 80/20 to 95/5.

Examples of ethylene/α-olefin copolymers for the graft-modifiedethylene/α-olefin copolymer rubbers (i) as mentioned above includebinary component copolymers such as an ethylene/propylene copolymer, anethylene/butene-1copolymer, an ethylene/4-methylpentene-1 copolymer, anethylene/hexene-1 copolymer, an ethylene/octene-1 copolymer and anethylene/decene-1 copolymer; and

multicomponent copolymers such as an ethylene/propylene/1,4-hexadienecopolymer, an ethylene/propylene/dicyclopentadiene copolymer, anethylene/propylene/5-ethylidene-2-norbornene copolymer, anethylene/propylene/2,5-norbornadiene copolymer, anethylene/butene-1/dicyclopentadiene copolymer, anethylene/butene-1/1,4-hexadiene copolymer and anethylene/butene-1/5-ethylidene-2-norbornene copolymer.

In the graft-modified propylene/α-olefin copolymer rubber (ii) , themolar ratio (propylene/α-olefin) of propylene to α-olefin is preferably50/50 to 95/5, though it varies depending on the types of α-olefinsused. When α-olefin used is 1-butene, the molar ratio is preferably50/50 to 90/10, and when α-olefin used is one having at least 5 carbonatoms, the molar ratio is preferably 80/20 to 95/5.

The α-olefin random elastomeric copolymer may contain, in addition tothose derived from α-olefins, further constituent units such as thosederived from diene compounds as in the above-mentioned multicomponentcopolymers, if characteristics of the α-olefin random elastomericcopolymer are not deteriorated.

These constituent units which may be contained in the α-olefin randomcopolymer include, for example, those derived from chain non-conjugateddienes such as 1,4-hexadiene, 1,6-octadiene, 2-methyl-1,5-hexadiene,6-methyl-1,5-heptadiene and 7-methyl-1,6-octadiene;

constituent units derived from cyclic non-conjugated dienes such ascyclohexadiene, dicyclopentadiene, methyl tetrahydroindene,5-vinylnorbornene, 5-ethylidene-2-norbornene, 5-methylene-2-norbornene,5-isopropylidene-2-norbornene and6-chloromethyl-5-isopropenyl-2-norbornene;

constituent units derived from further diene compounds such as2,3-diisopropylidene-5-norbornene,2-ethylidene-3-isopropylidene-5-norbornene and2-propenyl-2,2-norbornadiene; and further

constituent units derived from cycloolefins.

The content of the above-mentioned diene constituent units in theα-olefin random elastomeric copolymer is usually not more than 10% bymol, preferably not more than 5% by mol.

The graft-modified α-olefin random elastomeric copolymer used in thepresent invention may be prepared by graft-modifying the unmodifiedα-olefin random elastomeric copolymers as mentioned above withunsaturated carboxylic acids, anhydrides thereof or derivatives thereof.

Examples of unsaturated carboxylic acids used herein include acrylicacid, methacrylic acid, α-ethylacrylic acid, maleic acid, fumaric acid,itaconic acid, citraconic acid, tetrahydrophthalic acid,methyltetrahydrophthalic acid,endocis-bicyclo[2.2.1]hept-5-en-2,5-dicarboxylic acid (Nadic Acid™) andmethyl-endocis-bicyclo[2.2.1]hept-5-en-2,5-dicarboxylic acid(Methylnadic Acid™). Preferred examples of unsaturated carboxylic acidanhydrides include maleic anhydride, citraconic anhydride, Nadic Acidanhydride and Methylnadic Acid anhydride. Usable as the unsaturatedcarboxylic acid derivatives are acid halide compounds (e.g. maleylchloride), imide compounds (e.g. maleimide) and ester compounds (e.g.monomethyl maleate, dimethyl maleate and glicidyl maleate).

These graft modifiers may be used either singly or in combination.

Of the above-mentioned graft modifiers, it is preferable to use theunsaturated carboxylic acid anhydrides, especially maleic anhydride orNadic Acid anhydride.

The graft-modification of the above-mentioned α-olefin random copolymermay be conducted, for example, by a method where the ungraft-modifiedcopolymer is suspended or dissolved in a solvent, and the graft modifieris added to the suspension or solution to carry out the graft-modifyingreaction (solution method), and by a method where the graft-modifyingreaction is carried out while melting a mixture of the ungraft-modifiedcopolymer and the graft modifier (melting method).

The above-mentioned graft-modified α-olefin random copolymer and thegraft-modified vinyl aromatic hydrocarbon/conjugated diene copolymer orhydrogenation product thereof (B), the latter two components of whichwill be illustrated later, may be a graft modification product which maybe prepared by mixing a corresponding unmodified polymer and a graftmodifier in amounts such that a desired graft ratio is obtained, or bydiluting a corresponding graft-modified product having a high graftratio previously prepared with a corresponding unmodified polymer toobtain a desired graft ratio.

The amount of graft modifier used in the graft reaction may be decidedtaking the reactivity of the modifier into consideration, and isgenerally in the range of 1-10 parts by weight based on 100 parts byweight of the unmodified α-olefin random elastomeric copolymer.

By the graft reaction in this manner, there may be obtained agraft-modified α-olefin random elastomeric copolymer in which the graftmodifier has been graft polymerized on the unmodified α-olefin randomelastomeric copolymer in an amount of usually 0.0-10 parts by weight,preferably 0.05-5 parts by weight, especially 0.1-3 parts by weight, per100 parts by weight of the unreacted elastomeric copolymer.

In carrying out the graft reaction, the graft efficiency can be improvedby the use of a radical initiator. There can be used known radicalinitiators such as organic peroxides, organic peresters and azocompounds. The amount of the radical initiator is usually 0.01-20 partsby weight, based on 100 parts by weight of the unmodified α-olefinrandom elastomeric copolymer.

Of the graft-modified α-olefin random elastomeric copolymers asillustrated above, the use of a graft-modified ethylene/propylene randomcopolymer rubber or graft-modified ethylene/α-olefin random copolymerrubber which has an ethylene content of 35-50% by mol and issubstantially amorphous can provide effective reduction in loss oftoughness of the connector by heat deterioration.

The graft-modified vinyl aromatic hydrocarbon/conjugated diene copolymer(B) used in the composition of the invention is a graft modified productof a random or block copolymer of a vinyl aromatic hydrocarbon and aconjugated diene compound, and a hydrogenation product of the graftmodified copolymer may also be used.

Specific examples of the vinyl aromatic hydrocarbon/conjugated dienecopolymers or hydrogenation products thereof used for preparing theabove-mentioned graft-modified product include styrene/butadiene blockcopolymer rubbers, styrene/butadiene/styrene block copolymer rubbers,styrene/isoprene block copolymer rubbers, styrene/isoprene/styrene blockcopolymer rubbers, hydrogenated styrene/butadiene/styrene blockcopolymer rubbers, hydrogenated styrene/isoprene/styrene block copolymerrubbers and styrene/butadiene random copolymer rubbers. In thehydrogenated copolymer rubbers as referred to above, the double bondsremaining in the copolymer rubbers have been partly or fullyhydrogenated.

In these copolymers, the molar ratio (vinyl aromatichydrocarbon/conjugated diene) of the recurring units derived from thevinyl aromatic hydrocarbon to the recurring units derived from theconjugated diene is usually 10/90 to 70/30, preferably 20/80 to 50/50.

The vinyl aromatic hydrocarbon/conjugated diene copolymer orhydrogenation product thereof has an intrinsic viscosity (η), asmeasured in decalin at 135° C., of usually 0.01-10 dl/g, preferably0.08-7 dl/g; a glass transition temperature (Tg) of usually not morethan 0° C. preferably not more than -10° C., especially not more than-20° C.; and a crystallinity, as measured by X-ray diffractometry, of0-10%, preferably 0-7%, especially 0-5%.

The graft-modified vinyl aromatic hydrocarbon/conjugated diene copolymerused in the invention may be prepared in the same manner as in thepreparation of the above-mentioned graft-modified α-olefin randomelastomeric copolymer by graft-modifying the unmodified vinyl aromatichydrocarbon/conjugated diene copolymer with unsaturated carboxylicacids, anhydrides thereof or derivatives thereof.

Examples of the unsaturated carboxylic acids, anhydrides thereof andderivatives thereof used herein include those compounds used inpreparing the above-mentioned graft-modified α-olefin random elastomericcopolymer. These compounds may also be used either singly or incombination.

Of these graft modifiers, preferred are unsaturated carboxylic acidanhydrides and especially maleic anhydride or Nadic Acid anhydride.

The graft polymerization of such graft modifier on the above-mentionedunmodified copolymer or hydrogenation product thereof may be carried outby a solution method and a melting method as described in themodification of α-olefin random elastomeric copolymer.

In the graft reaction, the amount of the graft modifier used is decidedtaking the reactivity of the modifier into consideration, and the graftmodifier is generally used in an amount of 1-10 parts by weightpreferably 1-5 parts by weight, based on 100 parts by weight of theunmodified vinyl aromatic hydrocarbon/conjugated diene copolymer orhydrogenation product thereof. In the graft reaction, there may also beused radical initiators such as organic peroxides, organic peresters andazo compounds in a similar manner as mentioned above.

By carrying out the graft reaction in the manner as mentioned above,there can be obtained a graft-modified vinyl aromatichydrocarbon/conjugated diene copolymer or hydrogenation product thereof,in which the graft modifier has been graft polymerized in an amount ofusually 0.01-10 parts by weight, preferably 0.05-5 parts by weight,based on 100 parts by weight of the unmodified aromatic vinylhydrocarbon/conjugated diene copolymer or hydrogenation product thereof.

The graft-modified vinyl aromatic hydrocarbon/conjugated diene copolymeror hydrogenation product thereof thus obtained is a low crystalline oramorphous copolymer, and a substantially amorphous copolymer ispreferred. That is, of these graft-modified copolymers, those having acrystallinity, as measured by X-ray diffractometry, of not more than10%, preferably not more than 7%, especially not more than 5% are used,and those having a crystallinity of substantially 0% are particularlypreferred. Accordingly, many of the graft-modified vinyl aromatichydrocarbon-nonconjugated diene copolymers or hydrogenation productsthereof do not exhibit a distinct melting point. Further, because oftheir low crystallinity, these graft-modified aromatichydrocarbon/conjugated diene copolymers or hydrogenation productsthereof are soft, and have a tensile modulus of usually at least 0.1/cm² and less than 20000 kg/cm², preferably 1 kg/cm² to 15000 kg/cm².

The graft-modified vinyl aromatic hydrocarbon/conjugated diene copolymeror hydrogenation product thereof has a melt index (as measured at 190°C.) of usually 0.1-30 g/10 min, preferably 1.0-20 g/10 min, especially2.0-15 g/10 min.

The graft-modified vinyl aromatic hydrocarbon/conjugated diene copolymeror hydrogenation product thereof has a glass transition temperature (Tg)of usually -150° to +50° C., preferably -80° to -20° C.; and anintrinsic viscosity (η), as measured in decalin at 135° C., of usually0.0-10 dl/g, preferably 1-5 dl/g.

By the use of such graft-modified vinyl aromatic hydrocarbon/conjugateddiene copolymer or hydrogenation product thereof, there can be attainedeffective reduction in loss of toughness of the connector by heatdeterioration. When the connector is intended to be used at hightemperatures and for a long period of time, the use of the hydrogenationproduct is particularly preferred.

Among the above-mentioned graft-modified α-olefin random copolymers andthe graft-modified vinyl aromatic hydrocarbon/conjugated dienecopolymers or hydrogenation products thereof (B) , it is particularlypreferable to use in the present invention a graft-modifiedethylene/propylene copolymer, and a graft modified and hydrogenatedproduct of a styrene/butadiene/styrene block copolymer.

In the present invention, the graft-modified α-olefin random copolymer,the graft-modified vinyl aromatic hydrocarbon/conjugated diene copolymeror hydrogenation product thereof (B) may be used either singly or incombination. It is particularly preferable to use a mixture of bothcomponents in about equal amounts from the standpoint of an excellentbalance among various physical properties.

Into the above-mentioned graft-modified α-olefin random copolymer and/orthe graft-modified vinyl aromatic hydrocarbon/conjugated diene copolymeror hydrogenation product thereof (B), other polymers or copolymers maybe incorporated to an extent such that characteristics of these resinsare not deteriorated.

Mold Release Agent (C)

The resin composition used in the present invention contains thearomatic polyamide (A) and the graft-modified copolymer (B) as mentionedabove, and further a mold release agent (C) selected from the groupconsisting of polyethylene waxes and metallic salts of specificaliphatic carboxylic acids.

The polyethylene wax used herein is a polymer of ethylene having anaverage molecular weight (as measured by viscometry) of usually500-11000, preferably 1000-3000.

The softening temperature of the polyethylene wax is usually 110°-145°C., preferably 125°-135° C. The polyethylene wax is usually ahomopolymer of ethylene, but an α-olefin other than ethylene may becopolymerized to an extent such that the characteristics of theresulting copolymer wax are not deteriorated. In this case, the amountof the α-olefin other than ethylene to be copolymerized is usually 0-45%by weight.

The metallic salt of carboxylic acid (C) used in the invention includesmetallic salts of aliphatic carboxylic acids having 26-32 carbon atoms.Specific examples of the metallic salts of aliphatic carboxylic acidhaving 26-32 carbon atoms include metallic salts of cerotic acid,montanic acid and melissic acid. The metals that form salts with thesealiphatic carboxylic acids are those belonging to the group I, II andIII of the periodic table. Specific examples of these metallic salts ofaliphatic carboxylic acid having 26-32 carbon atoms are calciummontanate, sodium montanate and lithium montanate. Sodium salts arepreferred and sodium salts of montanic acid, which is commerciallyavailable for example from Hoechst Japan under the trade name HostamontNAV-101, is particularly preferred.

The polyethylene waxes and metallic salts of aliphatic carboxylic acidshaving 26-32 carbon atoms mentioned above may be used either singly orin combination.

Because calcium stearate or magnesium stearate which is conventionallyused as a mold release agent for an aliphatic polyamide resin, foams thecomposition comprising the above-mentioned aromatic polyamide (A) andgraft-modified copolymer (B) according to the invention at the time ofmolding, the resulting connector fails to exhibit favorable physicalproperties.

The resin composition used for the preparation of the connectors of theinvention contains the aromatic polyamide (A) in an amount of 65-90% byweight, preferably 70-80% by weight and the graft-modified copolymer (B)in an amount of 10-35% by weight, preferably 20-30% by weight, with theproviso that the sum total of the aromatic polyamide (A) andgraft-modified copolymer (B) is 100% by weight; and further the moldrelease agent (C) in an amount, based on 100% by weight the sum total ofthe aromatic polyamide (A) and graft-modified copolymer (B) , of0.1-1.0% by weight, preferably 0.1-0.5% by weight.

The polyamide resin compositions used for forming the connectors of thepresent invention has a specific gravity of usually about 1.05-1.12,preferably about 1.07-1.10. This specific gravity is lower than those ofresins widely used for making connectors, such as polybutyleneterephthalate having a specific gravity of about 1.31 and nylon 66having a specific gravity of about 1.14. Accordingly, the use of theabove-mentioned polyamide resin compositions makes it possible to savethe weight of connectors.

Antioxidant (D)

The resin composition comprising the above-mentioned specific aromaticpolyamide (A), graft-modified copolymer (B) and mold release agent (C)used for the preparation of the connectors of the invention may furthercontain an antioxidant (D). Examples thereof include known antioxidantssuch as phenol, sulfur and phosphorous antioxidants. Of theseantioxidants, particularly preferred are hindered phenol and sulfurantioxidants.

The hindered phenol antioxidant having a molecular weight usually of atleast 500, preferably at least 540, especially at least 600, exhibits ahigh effectiveness. It is preferable that the hindered phenolantioxidant has a temperature, at which a reduction in its weight by 10%in a thermogravimetric analysis curve, as measured in air (TGA 10%weight reduction temperature), corresponds to usually at least 300° C.,preferably at least 320° C., especially at least 350° C. Thethermogravimetric analysis curve may be obtained by measurement at aheating rate of 10° C./min using a thermal analyzer TG-DTA from RigakuDenki K.K. The hindered phenol antioxidants having the above-mentionedmolecular weight and TGA temperature are difficult to decompose underheat during molding.

Examples of the hindered phenol antioxidants having such characteristicsinclude those as listed below.

n-Octadecyl-3-(4'-hydroxy-3',5'-di-tert-butylphenyl) propionate:(molecular weight 530, TGA 10% weight reduction temperature 305° C.),

1,1,3-Tris(2-methyl-4-hydroxy-5-tert-butylphenyl) butane: (molecularweight 544, TGA 10% weight reduction temperature 323° C.),

1,3,5-Trimethyl-2,4,6-tris (3,5-di-tert-butyl-4-hydroxyphenyl)benzylbenzene: (molecular weight 774, TGA 10% weight reductiontemperature 338° C.),

1,3,5-Tris(4-hydroxy-3,5-di-tert-butylbenzyl)-s-triazine-2,4,6-(1H,3H,5H)-trione:(molecular weight 783, TGA 10% weight reduction temperature 347° C.),

Ethylene glycol-bis[3,3-bis(3'-tert-butyl-4-hydroxyphenyl)butylate]:(molecular weight 794, TGA 10% weight reduction temperature 344° C.),

Tetrakis[methylene-3-(3,5-di-tert-butyl-4-hydroxyphenyl)propionate]methane: (molecular weight1176, TGA 10% weight reduction temperature 355° C.),

3,9-Bis[2-{3- (3-tert-butyl-4-hydroxy-5-methylphenyl)propionyloxy}-1,1-dimethylethyl]-2,4,8,10-tetraoxaspiro[5,5]undecane:(molecular weight 741, TGA 10% weight reduction temperature 372° C.),

1,6-Hexanediol-bis[3-(3,5-di-tert-butyl-4-hydroxyphenyl) propionate]:(molecular weight 639, TGA 10% weight reduction temperature 314° C.),

Triethylene glycol-bis[3-(3-tert-butyl-5-methyl-4-hydroxyphenyl)propionate]: (molecular weight 587, TGA 10% weight reduction temperature311° C.),

N,N'-hexamethylene-bis(3,5-tert-butyl-4-hydroxycinnamamide): (molecularweight 637, TGA 10% weight reduction temperature 330° C.),

N,N'-bis[3-(3,5-di-tert-butyl-4-hydroxyphenyl) propionyl]hydrazine:(molecular weight 553, TGA 10% weight reduction temperature 304° C.),

2,2'-oxamido-bis-ethyl-3-(3,5-di-tert-butyl-4-hydroxyphenyl) propionate:(molecular weight 697, TGA 10% weight reduction temperature 323° C.),

2,2'-methylene-bis (4-methyl-6-tert-butylphenol) terephthalate:(molecular weight 810, TGA 10% weight reduction temperature 327° C.),

1,3,5-Tris[(3,5-di-tert-butyl-4-hydroxyphenyl) propionyloxyethyl)isocyanurate: (molecular weight 1045, TGA 10% weight reductiontemperature 346° C.),

2,2'-thio-diethylenebis [3-(3,5-di-tert-butyl-4-hydroxyphenylpropionate], and

2,2'-bis[4-{2-(3,5-di-tert-butyl-4-hydroxyhydrocinnamoyloxy)}ethoxyphenyl]propane:(molecular weight 836).

These compounds may be used either singly or in combination.

Of these hindered phenol antioxidants, preferred are polyhydric,preferably two or more hydric phenols, and particularly preferred are:

3,9-bis[2-{3-(3-tert-butyl-4-hydroxy-5-methylphenyl)propionyloxy}-1,1-dimethylethyl]-2,4,8,10-tetraoxaspiro{5,5}undecane,

N,N'-hexamethylenebis (3,5-di-tert-butyl-4-hydroxycinnamamide),

1,1,3-tris(2-methyl-4-hydroxy-5-tert-butylphenyl) butane and

n-octadecyl-3-(4'-hydroxy-3',5'-di-tert-butylphenyl) propionate.

It has been found that the sulfur antioxidant having a molecular weightof usually at least 600, preferably at least 620, especially at least650, exhibits a high effectiveness. The sulfur antioxidant has atemperature, at which a reduction in its weight by 10% in athermogravimetric analysis curve, as measured in air (TGA 10% weightreduction temperature), corresponds to usually at least 280° C.,preferably at least 290° C., especially at least 300° C. The sulfurantioxidants having the above-mentioned molecular weight and TGAtemperature are difficult to decompose under heat during molding.

Further, as the sulfur antioxidant, compounds represented by thefollowing formula [III]may be preferably used:

    (R.sup.1 S--R.sup.2 --COOCH.sub.2).sub.4 C                 [III]

wherein R¹ is a hydrocarbon radical having usually 3-20 carbon atoms,preferably 5-20 carbon atoms, R² is a divalent hydrocarbon radicalhaving usually 1-5 carbon atoms, preferably 1-3 carbon atoms, and thefour sulfur-containing groups attached to the carbon atom may be eitherthe same or different.

A specific example of the compounds of the formula [III]is:

Penta (erythrityl-tetra-β-mercaptolauryl) propionate: (molecular weight1160, TGA 10% weight reduction temperature 300° C.).

As the sulfur antioxidant, there may also be used compounds representedby the following formula [IV], in addition to the compounds of theformula [III]:

    S(R.sup.4 --COOR.sup.3).sub.2                              [IV]

wherein R³ is an alkyl group having usually 15-30 carbon atoms,preferably 18-30 carbon atoms, which optionally contains a sulfur atom,and R⁴ is a divalent aromatic group which optionally carries an alkylgroup, a divalent alicyclic alkyl group which optionally carries analkyl group, a divalent alkyl group or a single bond.

Specific examples of the compounds of the formula [IV] include:

Distearylthio-di-1,1'-methylpropionate: (molecular weight 696, TGA 10%weight reduction temperature 296° C.),

Myristylstearylthio dipropionate: (molecular weight 626, TGA 10% weightreduction temperature 284° C.),

Distearylthio dipropionate: (molecular weight 682, TGA 10% weightreduction temperature 292° C.), and

Distearylthio dibutyrate: (molecular weight 710, TGA 10% weightreduction temperature 296° C.).

Of the sulfur antioxidants illustrated above, the compounds of theformula [III]exhibit particularly excellent heat stability in theabove-mentioned specific aromatic polyamide.

In the resin composition used according to the invention, either thehindered phenol antioxidant or sulfur antioxidant, or both areincorporated in an amount, based on 100 parts by weight of the resincomponents, of usually 0.2-4 parts by weight, preferably 0.5-2 parts byweight. It is particularly preferable to use both the hindered phenoland sulfur antioxidants, and the weight ratio of the hindered phenolantioxidant to the sulfur antioxidant is in the range of usually 1:5 to5:1, preferably 1:3 to 3.5:1.

The thermoplastic resin composition used according to the invention maybe incorporated with further additives, such as inorganic fillers,organic fillers, heat stabilizers, weathering stabilizers, antistaticagents, anti-slip agents, anti-blocking agents, anti-fogging agents,lubricants, pigments, dyes, natural oils and synthetic oils, so long asthey do not deteriorate the characteristics of the composition.

Further, the composition may be mixed with other heat resistingthermoplastic resins to an extent such that they do not also deterioratecharacteristics of the composition. Examples of such heat resistingresins include PPS (polyphenylene sulfide) , PPE (polyphenylene ether),PES (polyether sulfone), PEI (polyether imide) , LCP (liquid crystalpolymer) and modification products of these resins. In the presentinvention, the use of polyphenylene sulfide is particularly preferred.

The content of the heat resisting thermoplastic resin in the compositionis usually less than 50% by weight, preferably 0-40% by weight.

Connector

For the preparation of the connectors of the invention, a resincomposition is first prepared by mixing and melting the above-mentionedaromatic polyamide (A), graft modified elastomeric copolymer (B), andmold release agent compound (C), and, optionally, antioxidant (D). Inthat case, there may be used ordinary kneading devices such as anextruding machine and a kneader. The mold release agent (C) may be addedto the resin composition after preparation thereof.

With the resin composition thus obtained, a connector main body, forexample connector housings which are depicted in FIGS. 1 and 2, may beprepared by means of conventionally used methods such as an injectionmolding technique.

As shown in FIGS. 1 and 2, the connector of the invention comprises afemale connector housing 1 and a male connector housing 2, both beingformed from the above-mentioned polyamide resin composition. In thefemale connector housing 1, there are formed a plurality of terminalinserting chambers 3a, and in each of the terminal inserting chambers3a, a female terminal 4 is supported by means of a terminal hookingmember (lance) 5 formed integrally with the female connector housing. Onthe other hand, in the male connector housing 2, there are also formed aplurality of terminal inserting chambers 3b, and in each of the terminalinserting chambers 3bof the male terminal connector housing, a maleterminal 6 is supported by means of a terminal hooking member (lance) 5bformed integrally with the male connector housing 2 so as to the maleterminal 6 is capable of contacting with the female terminal 4 of thefemale connector housing 1 when the male connector housing 2 is fittedwith the female connector housing 1. In the connector of the inventionhaving such a structure, a first half front portion of the maleconnector housing 2 is fitted to a fitting portion 7 of a first halffront portion of the female connector housing 1, whereby the bothconnector housings are engaged to each other by means of a holding meanscomprising an elastic holding member 8 and a holding projection 9, andthe female terminals 4 and the male terminals 6 are connectedelectrically with each other.

The connector of the present invention having such a structure asmentioned above not only can be used as a conventional connector, butalso is particularly suitable for use under conditions where heating andcooling are repeated as in an automotive engine room, because theconnector of the invention has excellent heat resistance and less indrop of toughness caused by heating the connector. For example, when anconventional connector is used in an automotive engine room, toughnessthereof is dropped by heating, resulting in decrease in servicedurability. In contrast, the connector of the invention hardly sufferssuch a drop in toughness, so that it keeps a necessary extensibilityeven after heat aging.

The connector of the present invention does not decrease in toughnesseven after exposure to high temperature for a long period of time.

The resin composition used according to the invention for forming thehousings of the connector of the invention has excellent mold releasecharacteristics, so that the resin composition can provide moldedhousings at a high productivity rate.

In addition, the resin composition used for the connector housings ofthe invention has a lower specific gravity than those of resins forconventional connectors, so that it can contribute in saving the weightof connector.

Further, the resin composition used for the connector housings of theinvention exhibits a low water absorption and excellent chemicalresistance, and hence the connector formed from the composition has highdimensional stability even when the connector is brought into contactwith water.

EXAMPLES

The present invention is further illustrated with reference to thefollowing examples, but it should be construed that the invention is inno way limited to those examples.

Synthesis Example 1

Aromatic Polyamide (A) was prepared in the manner as described below.

Preparation of Aromatic Polyamide (A)

A 1-liter reactor was charged with 255.6 g (2.2 mol) of1,6-diaminohexane, 201 g (1.2 mol) of terephthalic acid, 144.7 g (0.99mol) of adipic acid, 0.45 g (4.25×10⁻³ mol) of sodium hypophosphite as acatalyst, and 148 ml of deionized water, purged with nitrogen and thenthe reaction was carried out for 1 hour at 250° C. and 35 kg/cm². Themolar ratio of terephthalic acid to adipic acid is 55:45.

After the reaction time of 1 hour, the reaction product was withdrawnfrom the reactor into a container which was connected to the reactor andkept an internal pressure lower by about 10 kg/cm² than that of thereactor, to obtain 545 g of a polyamide precursor having an intrinsicviscosity (η) (as measured at 30° C. in a concentrated sulfuric acid) of0.15 dl/g.

Subsequently, the polyamide precursor was dried and polymerized bymelting in a twin-screw extruder at a cylinder temperature of 30° C. toobtain an aromatic polyamide.

This polyamide, named Aromatic Polyamide A, had the followingcomposition. In the dicarboxylic acid constituent units, the content ofthe terephthalic acid constituent units is 55% by mol and that of theadipic acid constituent units is 45% by mol. Physical properties of thepolyamide were:

Intrinsic viscosity

(at 30° C. in a concentrated sulfuric acid) . . 1.0 dl/g Melting point .. . 313° C. Glass transition temperature . . . 80° C.

Synthesis Example 2

In the manner as described below, two types of modified copolymers[Modified Copolymer (B-a), and Modified Copolymer (B-b)]were obtained.

Preparation of Modified Copolymer (B-a)

An ethylene/propylene copolymer rubber having a molar ratio of ethyleneto propylene of 81:19 was prepared by a conventional method. Thiscopolymer had an intrinsic viscosity (η), as measured at 135° C. indecalin, of 2.19 dl/g.

Maleic anhydride was graft polymerized on this ethylene/propylenecopolymer rubber by a conventional method to obtain a maleicanhydride-graft modified ethylene/propylene copolymer rubber. The amountof maleic anhydride grafted was 0.77% by weight.

Preparation of Modified Copolymer (B-b)

Maleic anhydride was graft polymerized on a hydrogenatedstyrene/butadiene/styrene block copolymer (styrene content: 30% byweight; Trade name: Krayton G available from Shell Chemical Co.) toobtain a maleic anhydride-graft modified and hydrogenatedstyrene/butadiene/styrene block copolymer. The amount of maleicanhydride grafted was 1.94% by weight.

Example 1

80 parts by weight of Aromatic Polyamide (A) obtained in SynthesisExample 1, 20 parts by weight of Modified Copolymer (B-a) obtained inSynthesis Example 2, 0.25 part by weight of sodium montanate (Tradename: Hostamont NAV 101 available from Hoechst Japan), 0.5 part byweight of a phenol antioxidant (Trade name: Sumirizer GA-80 availablefrom Sumitomo Chemical Co.) and 0.5 part by weight of a sulfurantioxidant (Trade name: Synox 412S available from Sypro Kasei K.K.)were mixed, and then pelletized using a twin-screw extruder (PCM45manufactured and sold by Ikegai Tekko K.K.) at a cylinder temperatureset to 320° C.

The thus obtained pellets of the polyamide resin composition wereinjection molded to obtain test specimens and connectors having requiredsizes and shapes.

Injection molding conditions:

Injection molding machine: IS55EPN manufactured by Toshiba Kikai K.K.

Cylinder temperature: 320° C.

Mold temperature: 50° C.

Injection pressure: 900 kg/cm²

Method for evaluation:

(1) Specific gravity:

Measured according to ASTM D792.

(2) Water absorption:

Measured according to ASTM D570. A test specimen of 3.2×12.7×127 mm wasimmersed in water at 23° C. for 24 hours and then the water absorptionwas determined.

(3) Izod impact strength:

Measured according to ASTM D256 (notched).

(4) Tensile strength and tensile elongation:

Measured according to ASTM D638 on an ASTM test specimen No. 4 of 2 mmthick at a stress rate of 5 mm/min.

(5) Heat resistance:

The tensile elongation was measured under the same conditions as above,except that the ASTM test specimen which had been allowed to stand in anair oven kept at 150° C. for 500 hours was used. The smaller is the dropin tensile elongation, the better is the heat resistance.

(6) Mold release characteristics:

A closed-end cylindrical specimen was molded using a mold equipped witha device for measuring a mold release force as shown in FIG. 3, and aforce required to release the molded specimen from the mold wasmeasured.

That is, as shown in FIG. 3, a resin composition is filled into a roomformed between a male mold 16 and a female mold 17 adapted for forming acup-like molded article through a spool runner 11 to prepare a cup-likemolded article 12. After cooling, the molds 16 and 17 are released, andthe cup-like molded article 12 is pushed out by means of a pushing pin13 provided at the center of the male mold 16. A pressure applied to thepushing pin 13 for taking the molded article out of the molds ismeasured by means of a pressure sensor 14, and the measured value isrecorded by means of a mold release force recorder 15.

The molds are designed to form a closed cylindrical test specimen of 20mm in diameter, 20 mm in depth and 1 mm in wall thickness.

Example 2

Example 1 was repeated except that Modified Copolymer (B-b) was used inplace of Modified Copolymer (B-a).

Example 3

Example 1 was repeated except that a polyethylene wax (Trade name:Highwax 200 P available from Mitsui Petrochemical, Ltd.) was used inplace of the sodium montanate as the mold release agent (C) .

Comparative Example 1

Example 1 was repeated except that the use of mold release agent (C) wasomitted.

Comparative Example 2

Example 1 was repeated except that calcium stearate was used in place ofsodium montanate.

Comparative Example 3

Example 1 was repeated except that nylon 66 (Trade name: 2020UW1available from Ube Industries, Ltd.) was used in place of the aromaticpolyamide resin composition.

Comparative Example 4

Example 1 was repeated except that polybutylene terephthalate (PBT,Trade name: BT1000S-01 available from Dainippon Ink K.K.) was used inplace of the aromatic polyamide resin composition.

The compositions and evaluation results of the above Examples andComparative Examples are shown in Tables 1 and 2.

                                      TABLE 1                                     __________________________________________________________________________           Ex. 1                                                                             Ex. 2                                                                             Ex. 3                                                                             Comp. Ex. 1                                                                          Comp. Ex. 2                                                                          Comp. Ex. 3                                                                          Comp. Ex. 4                           __________________________________________________________________________    Aromatic                                                                             80  80  80  80     80     NY66   PBT only                              Polyamide                        only                                         (A)                                                                           Modified                                                                             20  --  20  20     20                                                  Copolymer                                                                     (B-a)                                                                         Modified                                                                             --  20  --  --     --                                                  Copolymer                                                                     (B-b)                                                                         Mold release                                                                         0.5 0.5 --  --     --                                                  agent C                                                                       (NAV 101)                                                                     Mold release                                                                         --  --  0.5 --     --                                                  agent C                                                                       (200P)                                                                        Mold release                                                                         --  --  --  --     0.5                                                 agent C (Ca                                                                   stearate)                                                                     NY 66  --  --  --  --     --     100    --                                    PBT    --  --  --  --     --     --     100                                   Specific                                                                             1.10                                                                              1.10                                                                              1.10                                                                              1.10   1.10   1.14   1.31                                  gravity (- )                                                                  Water  0.3 0.3 0.3 0.3    0.3    1.2    0.02                                  absorption                                                                    (%)                                                                           Izod impact                                                                          70  70  70  80     10     7      5                                     strength                                                                      (kg.cm/cm)                                                                    Tensile                                                                              650 650 650 650    550    800    550                                   strength                                                                      (kg/cm.sup.2)                                                                 Tensile                                                                              50  60  50  50     15     80     130                                   elongation                                                                    (%)                                                                           Heat                                                                          resistance                                                                           20  20  20  20     5      25     8                                     (tensile                                                                      elongation                                                                    after 50 h at                                                                 150° C.) (%)                                                           Injection                                                                            good                                                                              good                                                                              good                                                                              good   foamed good   good                                  moldability                                                                   (-)                                                                           Mold release                                                                         4   5   5   >17    5      3      3                                     force              cannot be                                                  (kg/cm.sup.2)      taken out                                                  __________________________________________________________________________

                                      TABLE 2                                     __________________________________________________________________________                        Comp.                                                                              Comp.                                                                             Comp. Comp.                                                 Ex. 1                                                                            Ex. 2                                                                            Ex. 3                                                                            Ex. 1                                                                              Ex. 2                                                                             Ex. 3 Ex. 4                                      __________________________________________________________________________    Weight of connector                                                                       8.92                                                                             8.93                                                                             8.92                                                                            --    8.92                                                                              9.51 10.47                                      (g)                          (before                                                                       moisture                                                                      condition-                                                                    ing)                                             Initial stage                                                                 Lock releasability                                                                       good                                                                             good                                                                             good                                                                             --   good                                                                              good  good                                       Connector fitting                                                                        14.8                                                                             14.6                                                                             14.9                                                                             --   14.2                                                                              11.0  17.1                                       force (Kgf)                                                                   Terminal holding                                                                         13.8                                                                             13.5                                                                             13.2                                                                             --   13.6                                                                               9.1  11.8                                       force (female                                                                 housing) (Kgf)                                                                Heat resistance                                                               (after 200 hr at                                                              180° C.)                                                               Lock releasability                                                                       good                                                                             good                                                                             good                                                                             --   good                                                                              good  not good                                   Connector fitting                                                                        14.7                                                                             14.2                                                                             14.6                                                                             --   14.0                                                                              10.9  uumeasur-                                  force (Kgf)                        able                                       Terminal holding                                                                         13.7                                                                             13.7                                                                             13.5                                                                             --   13.3                                                                               8.9  unmeasur-                                  force (female                      able                                       housing) (Kgf)                                                                Injection moldability                                                                    good                                                                             good                                                                             good                                                                             good foamed                                                                            good  good                                       Mold release                                                                             good                                                                             good                                                                             good                                                                             unable *1                                                                          good                                                                              good  good                                       properties                                                                    __________________________________________________________________________     *1: Evolution could not be made because the molded article could not be       taken out of the molds.                                                  

What is claimed is:
 1. A connector having a housing which is formed froma polyamide resin composition comprising(A) 65-90% by weight of anaromatic polyamide having an intrinsic viscosity (η), as measured in aconcentrated sulfuric acid at 30° C., of 0.5-3.0 dl/g and a meltingpoint of exceeding 300° C.,said aromatic polyamide (A) being composed ofrecurring units comprising 50-100% by mol of terephthalic acidconstituent units, 0-50% by mol of aromatic dicarboxylic acidconstituent units other than the terephthalic acid constituent unitsand/or 0-50% by mol of aliphatic dicarboxylic acid constituent units,each of which has 4 to 20 carbon atoms, and recurring units comprisingaliphatic alkylenediamine constituent units and/or alicyclicalkylenediamine constituent units; and (B) 10-35% by weight of agraft-modified α-olefin random copolymer and/or a graft-modified vinylaromatic hydrocarbon/conjugated diene copolymer or a hydrogenationproduct thereof, with the proviso that the sum total of aromaticpolyamide (A) and graft-modified copolymer (B) is 100% by weight; and(C) 0.1-1.0% by weight, based on 100% by weight of the sum total ofaromatic polyamide (A) and graft-modified copolymer (B) , of at leastone compound selected from the group consisting polyethylene waxes andmetallic salts of aliphatic carboxylic acids having 26 to 32 carbonatoms.
 2. A connector having a housing which is formed from a polyamideresin composition comprising(A) 65-90% by weight of an aromaticpolyamide having an intrinsic viscosity (η), as measured in aconcentrated sulfuric acid at 30° C., of 0.5-3.0 dl/g and a meltingpoint of exceeding 300° C.,said aromatic polyamide (A) being composed ofrecurring units comprising 50-100% by mol of terephthalic acidconstituent units, 0-50% by mol of aromatic dicarboxylic acidconstituent units other than the terephthalic acid constituent unitsand/or 0-50% by mol of aliphatic dicarboxylic acid constituent units,each of which has 4 to 20 carbon atoms, and recurring units comprisingaliphatic alkylenediamine constituent units and/or alicyclicalkylenediamine constituent units; and (B) 10-35% by weight of agraft-modifiedα-olefin random copolymer and/or a graft-modified vinylaromatic hydrocarbon/conjugated diene copolymer or a hydrogenationproduct thereof, with the proviso that the sum total of aromaticpolyamide (A) and graft-modified copolymer (B) is 100% by weight; and(C) 0.1-1.0% by weight, based on 100% by weight of the sum total ofaromatic polyamide (A) and graft-modified copolymer (B), of at least onecompound selected from the group consisting polyethylene waxes andmetallic salts of aliphatic carboxylic acids having 26 to 32 carbonatoms; and (D) an antioxidant including a hindered phenol antioxidantand a sulfur antioxidant.
 3. The connector as claimed in claim 1 or 2wherein the dicarboxylic acid constituent units of said aromaticpolyamide (A) is composed of 50-80% by mol of terephthalic acidconstituent units, 0-40% by mol of aromatic dicarboxylic acidconstituent units other than terephthalic acid, and 20-50% by mol ofaliphatic dicarboxylic acid constituent units.
 4. The connector asclaimed in claim 1 or 2 wherein the graft-modified α-olefin randomcopolymer and/or graft-modified vinyl aromatic hydrocarbon/conjugateddiene copolymer or hydrogenation product thereof (B) is a graft-modifiedethylene/propylene copolymer and/or a hydrogenation product of agraft-modified stylene/butadiene/styrene block copolymer.
 5. Theconnector as claimed in claim 1 or 2 wherein component (C) is sodiummontanate.
 6. The connector as claimed in claim 2 wherein theantioxidant (D) comprises a hindered phenol antioxidant having amolecular weight of at least 500 and a sulfur antioxidant having amolecular weight of at least
 600. 7. The connector as claimed in claim 6wherein the hindered phenol antioxidant and sulfur antioxidant arepresent at a weight ratio in the range of from about 1:5 to 5:1.